Air-operated pressure indicating controller



April 8, 1952 E. E. LARSON ETAL 2,592,043

AIR-OPERATED PRESSURE INDICATING CONTROLLER Filed April 21, 1945[/755195 .5 L M77511 ff/ Patented Apr. 8, 1952 AIR-OPERATED PRESSUREINDICATIN G CONTROLLER Earl E. Larson, Wadsworth, and Charles B. Luther,Akron, Ohio, assignors to The B. F. Goodrich Company, New York, N. Y., acorporation of New York Application April 21, 1945, Serial No. 589,578

3 Claims.

This invention relates to air-operated pressure controllers and isespecially useful in controlling hydraulic apparatus.

Objects of the invention are to provide accurate control of highpressure, to provide control of pressure by use of a pressure gauge ofthe Bourdon type as a control actuating member, to provide throttlingcontrol of high pressures, and to provide safety of operation withaccurate control of pressure.

These and other objects will appear from the following description andthe accompanying drawing which is an elevation of the control mechanism.

Referring to the drawing, the numeral 10 designates a container which isto be maintained at substantially constant hydraulic pressure. For thispurpose the container is supplied from any source of fluid pressure,such as a pump, by a pipe II. A diaphragm operated valve l2 in thesupply line controls flow therethrough.

Connected to the container III by a pipe I3 is a pressure indicatinggauge M of the Bourdon tube type in which a Bourdon tube l 5 is directlyconnected to the pipe l3 and has its closed free end l6 connected by alinkage I! with a swinging gear sector l8 which in turn meshes with apinion IS on a rotatable stafi" 20. Mounted on the stall 20 is hub 2| towhich is secured a cam plate 22. This plate rotates with the stair.2lland is marked or engraved to indicate pressures. A stationary pointer23 is provided to cooperate with the cam plate 22 in indicatingpressures thereby providing for the cam plate to serve not only to givesensitive control of pressure but also direct, large scale visualindication of pressure.

The margin of the cam plate is formed with a cam surface having aconcentric raised portion 24 extending from the region of zero pressureof the marked portion to a region where the indicated pressure is thatdesired to be maintained in the container ID, as at 25. At that positionthe cam drops away to a lower level 26 through an inclined portion 21the shape of which determines the throttling range of the instrument,which shape can be made to give the desired breadth of throttling range,a more abrupt and shorter incline providing a narrower throttling range.

A cam roller 30 is freely mounted for rotation on an arm 3| pivotallymounted to a fixed member at 32, and rests upon the margin of the camplate.

A vane 33 is fixed to arm 3!. An air jet 34 is located so as todischarge air under pressure against the vane 33 and the vane increasesresistance of flow from the jet as it approaches the jet and decreasesresistance as it moves further away.

For controlling the valve l2 by the flow of air from the jet 34 aspermitted by the vane 33, a supply line 35 is provided with-a branch 36connecting it to a needle valve 31. The supply line 38 from the needlevalve 3'1 connects directly to a closed expansible elastic capsule 40and also to jet 34. A branch 4| of air line 35 delivers air underpressure to a valve 42. This valve is a three-way valve controlled by avalve ball 43 which is controlled by a rod 44 attached to capsule 40.Rod 44 extends loosely through an exhaust tube 45 arranged opposite adelivery tube 45 which is connected to the diaphragm of valve l2. Thearrangement is such that when pressure in capsule 40 is lowered, as byvane 33 moving away from jet 34, ball 43 is lowered closing exhaust pipe45, and air from line 35 enters line 4| and line. 46 raising the airpressure at valve l2 and closing that valve, and when pressure incapsule 40 is raised, as by vane 33 approaching jet 34, ball 42 israised, closing pipe 46, so that pressure in line 46 is lowered, andvalve I2 is opened. By adjustment of needle valve 3'! air pressureconditions may be so adjusted that very slight changes in pressure atjet 34 eiTect operation of valve l2 and a constant throttling of valvel2 takes place.

The arrangement has the advantage that very little force is required torotate the cam disc which is preferably made of light sheet material,such as aluminum, and the movements of the cam are therefore quiteaccurately efiected by the Bourdon tube. The vane 33 is also moved withslight force and its movements with respect to the jet 34 are verypositive in controlling air pressure to the valve l2, so that accuratecontrol of hydraulic pressure is made possible, while at the same time adirect, large scale visual indication of pressure is provided by thepressure indications on the cam disc, providing both pressure regulationand pressure indication by the single cam disc.

Variations may be made without departing from the scope of the inventionas it is defined by the following claims.

We claim:

1. Apparatus for simultaneously indicating and regulating hydraulicpressure, said apparatus comprising a member movable in response tochanges of hydraulic pressure, motion-trans mitting mechanism connectedto said member and including an element rotatable in response tomovement of said member, a disc mounted on said element for rotationtherewith and having pressure-indicating markings to indicate pressureand comprising a cam surface thereon, a cam follower on said cam, an airsupply, and means for controlling the flow of air including an air jetconnected to said air supply and a vane on said cam follower opposed tosaid jet and movable in response to movement of said cam follower.

2. Apparatus for simultaneously indicating and regulating hydraulicpressure in a line having an air-operated controlling valve, saidapparatus comprising a Bourdon tube connected to said line,motion-transmitting mechanism connected to said tube and including anelement rotatable in response to deflection of said tube, a disc mountedon said element for rotation therewith having pressure-indicatingmarkings to indicate pressure in said line, a cam surface thereon, a camfollower on said cam, an air supply to said air-operated valve, andmeans for controlling the flow of air to said valve including an air jetconnected to said air supply and a vane on said cam followeropposed tosaid jet and movable in response to movement of said cam follower.

3. Apparatus suitable for sensitively regulating high levels ofhydraulic pressure, an air pressure supply therefor, said apparatuscomprising a Bourdon tube, a disc mounted for rotation in response todeflection of said tube, and thereby in response to change in thehydraulic pressure, said disc having a cam surface thereon extendingthrough a limited are on the disc to provide by the extent of said are alimited throttling REFERENCES CITED The following references are ofrecord in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,301,405 Dexter Apr. 22, 19191,991,309 Annin Feb. 12, 1935 r 2,047,581 Grissett July 14, 19362,212,085 Tate Aug. 20, 1940 2,283,296 Temple May 19, 1942 2,366,246Erbguth Jan. 5, 1945 2,427,235 Smoot Sept. 9, 1947

